Unstability detection method and system, active noise reduction system and control method thereof

Abstract

The invention provides an instability detection method and system, an active noise reduction system and a control method thereof. The instability detection method is applied to an active noise reduction system. The active noise reduction system comprises a loudspeaker and a reference microphone; the instability detection method comprises the following steps: acquiring first sound feedback energy and first total energy of a first sound signal collected by a reference microphone; and in response to the first acoustic feedback energy and the first total energy meeting an instability condition, determining that the active noise reduction system is unstable. The active noise reduction system instability is determined by meeting the condition that the first acoustic feedback energy and the first total energy meet the instability condition. By calculating the first proportion and the first difference value, interference caused by abnormal sound of the external environment can be effectively offset, the phenomenon of misjudgment of instability of the active noise reduction system is further avoided, and therefore the instability detection method can more accurately judge whether the active noise reduction system is in the instability state or not.

Description

Technical Field

[0001] The present invention relates to the field of active noise reduction, and in particular to an instability detection method and system, an active noise reduction system and a control method thereof. Background Art

[0002] An active noise reduction system generally includes a reference microphone, a speaker, and a controller. Its working principle is: the sound signal obtained by the reference microphone is input into the controller to calculate the control signal of the sound signal, and the control signal is output through the speaker so that the control signal and the sound signal are offset, thereby achieving the effect of noise reduction.

[0003] For active noise reduction systems, stability is an important evaluation indicator. In order to avoid instability of the active noise reduction system, the instability detection method generally detects the stability of the active noise reduction system and takes corresponding measures when instability of the active noise reduction system is detected.

[0004] The commonly used instability detection method is to detect whether the output power of the control signal output by the speaker exceeds the threshold. If it exceeds, the instability detection system is judged to be unstable. However, when there are abnormal sounds from the outside, such as the collision sound of cooking, they will also be picked up by the reference microphone, and then the output power of the control signal of the speaker calculated based on the sound signal obtained by the reference microphone will increase to exceed the threshold, resulting in a false judgment of instability. Summary of the invention

[0005] The technical problem to be solved by the present disclosure is to overcome the defect that the instability detection method in the prior art may be disturbed by the external environment, resulting in misjudgment of instability, and to provide an instability detection method and system, and a control method and system for an active noise reduction system.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] In a first aspect, an instability detection method is provided, wherein the instability detection method is applied to an active noise reduction system; the active noise reduction system includes a speaker and a reference microphone; the instability detection method includes:

[0008] Acquire a first acoustic feedback energy and a first total energy of a first sound signal collected by the reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of the speaker and an acoustic feedback path;

[0009] In response to the first acoustic feedback energy and the first total energy meeting an instability condition, it is determined that the active noise reduction system is instability; wherein the instability condition includes at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference between the first total energy and the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than a ratio threshold and the first ratio gradually increases, and the first difference is less than a difference threshold and the first difference gradually increases.

[0010] Optionally, the step of determining the ratio threshold comprises:

[0011] When the active noise reduction system is not unstable, obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone to calculate a second ratio of the second acoustic feedback energy to the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the speaker and an acoustic feedback path;

[0012] After adjusting the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, a third acoustic feedback energy and a third total energy of the third sound signal collected by the reference microphone are obtained to calculate a third ratio of the third acoustic feedback energy to the third total energy; wherein the third acoustic feedback energy is obtained according to the third control signal of the speaker and the acoustic feedback path;

[0013] Selecting the ratio threshold within a numerical range from the second ratio to the third ratio;

[0014] and / or,

[0015] The step of determining the difference threshold comprises:

[0016] When the active noise reduction system is not unstable, obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone to calculate a second difference of the second acoustic feedback energy in the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the speaker and an acoustic feedback path;

[0017] After adjusting the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, a third acoustic feedback energy and a third total energy of the third sound signal collected by the reference microphone are obtained to calculate a third difference of the third acoustic feedback energy in the third total energy; wherein the third acoustic feedback energy is obtained according to the third control signal of the speaker and the acoustic feedback path;

[0018] The difference threshold is selected within a numerical range from the second difference to the third difference.

[0019] Optionally, adjusting the gain of the acoustic feedback path to simulate instability of the active noise reduction system includes:

[0020] The gain is reduced in a polling manner and in decreasing steps until the active noise reduction system becomes unstable.

[0021] Optionally, in response to the first acoustic feedback energy and the first total energy meeting an instability condition, determining that the active noise reduction system is instability includes:

[0022] In response to the first acoustic feedback energy and the first total energy acquired multiple times both meeting the instability condition, it is determined that the active noise reduction system is finally unstable.

[0023] In a second aspect, a control method for an active noise reduction system is provided, the control method comprising:

[0024] When it is determined that the active noise reduction system is unstable according to any of the above instability detection methods, the active noise reduction system is restarted.

[0025] Optionally, the active noise reduction system further includes a controller; the controller is used to convert the sound signal into a control signal; and restarting the active noise reduction system includes:

[0026] Obtaining the number of consecutive instability of the active noise reduction system;

[0027] In response to the number of consecutive instabilities being greater than or equal to a number threshold, the active noise reduction system is turned off and the controller is optimized; after restarting, the active noise reduction system performs active noise reduction based on the optimized controller.

[0028] In a third aspect, an instability detection system is provided, wherein the instability detection system is used to implement the instability detection method according to any one of the above claims; the detection system comprises:

[0029] An acquisition module, used to acquire a first acoustic feedback energy and a first total energy of a first sound signal collected by the reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of the speaker and an acoustic feedback path;

[0030] A response module is used to determine that the active noise reduction system is unstable in response to the first acoustic feedback energy and the first total energy meeting an instability condition; wherein the instability condition includes at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference between the first total energy and the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than a ratio threshold and the first ratio gradually increases, and the first difference is less than a difference threshold and the first difference gradually increases.

[0031] In a fourth aspect, an active noise reduction system is provided, characterized in that it is used to implement any of the control methods described above; the control system includes:

[0032] A detection module, configured to call a restart module when it is determined that the active noise reduction system is unstable according to any one of the above-mentioned instability detection methods;

[0033] A restart module is used to restart the active noise reduction system.

[0034] In a fifth aspect, a household appliance is provided, comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, characterized in that when the processor executes the computer program, the instability detection method described in any one of the above-mentioned methods or the control method of the active noise reduction system described in any one of the above-mentioned methods are implemented.

[0035] In a sixth aspect, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that when the computer program is executed by a processor, the instability detection method described in any one of the above or the control method of the active noise reduction system described in any one of the above is implemented.

[0036] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0037] The positive progress of the present disclosure is that the present disclosure determines the instability of the active noise reduction system by satisfying the instability condition of the first sound feedback energy and the first total energy. By calculating the first proportion and the first difference, the interference of the strange sound in the external environment can be effectively offset, thereby avoiding the occurrence of the phenomenon of misjudgment of the instability of the active noise reduction system. Therefore, the instability detection method can more accurately determine whether the active noise reduction system is in an unstable state. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of a frequency domain signal curve of a stable single-frequency abnormal sound, howling, and normal noise provided by an exemplary embodiment of the present disclosure;

[0039] Figure 2 A schematic diagram of a time domain signal curve of a stable single-frequency abnormal sound, howling, and normal noise provided by an exemplary embodiment of the present disclosure;

[0040] Figure 3 A flowchart of an instability detection method provided by an exemplary embodiment of the present disclosure;

[0041] Figure 4 A flow chart of determining a ratio threshold in an instability detection method provided by an exemplary embodiment of the present disclosure;

[0042] Figure 5 A flowchart of another instability detection method provided for an exemplary embodiment of the present disclosure;

[0043] Figure 6 A flow chart of a control method of an active noise reduction system provided by an exemplary embodiment of the present disclosure;

[0044] Figure 7 A schematic diagram of a module of an instability detection system provided by an exemplary embodiment of the present disclosure;

[0045] Figure 8 A schematic diagram of a module of an active noise reduction system provided by an exemplary embodiment of the present disclosure;

[0046] Fig. 9 The present invention is a schematic structural diagram of a household appliance according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0047] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0048] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0049] The instability detection of the active noise reduction system is a kind of abnormal sound emitted by the speaker of the active noise reduction system due to some faults or interference when the active noise reduction system is working, which affects the user experience. Abnormal sound includes howling and stable single-frequency abnormal sound (or stable single-frequency sound). The instability detection method provided in this embodiment can realize both the detection of howling and the detection of stable single-frequency abnormal sound.

[0050] The characteristics of howling caused by active noise reduction are: Figure 1 and Figure 2 There is a prominent peak in the noise spectrum. The amplitude of the highest point of the peak is significantly higher than the adjacent frequency, and the peak is generally much larger than the peak of the stable single-frequency abnormal sound, accounting for a large proportion of the overall noise power. From the beginning of the howling, its power amplitude in the time domain gradually increases from small to large. The ratio of the maximum power to the minimum power is generally more than 5 times, and the amplitude is generally close to or even exceeds the maximum sound power of the speaker itself. Figure 1The second to fifth columns of the table refer to the amplitudes at 94.28 Hz, 108.75 Hz, 0 Hz and 6000 Hz respectively, and the sixth column RMS data refers to the root mean square value of the amplitude from 0 to 6000 Hz. The amplitude can be characterized by, but not limited to, power, energy, or decibels.

[0051] Different from howling, the characteristics of stable single-frequency noise / stable single-frequency sound are: there is a prominent peak in the noise spectrum, the amplitude of the highest point of the peak (noise peak) is higher than the amplitude corresponding to the adjacent frequency, and the power of the peak accounts for a small proportion of the total noise power, that is, the power of the peak accounts for a proportion of the total noise power that is less than or equal to the power threshold, where the power threshold is calibrated according to experimental data. Figure 1 As shown by the blue curve, the peak bandwidth does not exceed 50Hz. Figure 2 When a stable single-frequency abnormal sound is generated, its power amplitude in the time domain is relatively stable, the power changes little, the ratio of maximum power to minimum power will not exceed 3 times, and the amplitude is generally much smaller than the maximum sound power of the speaker itself. Figure 2 The left ordinate represents the power amplitude, and the right ordinate represents the sound pressure amplitude, and the two can be converted into each other.

[0052] In order to reduce the misjudgment rate of instability of an active noise reduction system, an exemplary embodiment of the present invention provides an instability detection method. Figure 3 A flowchart of an instability detection method provided for an exemplary embodiment of the present disclosure, the instability detection method is applied to an active noise reduction system. The active noise reduction system includes at least a reference microphone, a speaker and a controller. The reference microphone is deployed near the noise source of the device equipped with the active noise reduction system, and the reference microphone is used to obtain the sound signal. After the sound signal is filtered by the calibrated controller, a control signal is obtained, which is played through the speaker to perform active noise reduction. It should be noted that the specific implementation method of the controller annotation method can be found in the relevant technical description, which will not be repeated here.

[0053] It should be noted that, in addition to range hoods, the active noise reduction system can also be used to reduce noise for household appliances such as dishwashers, refrigerators, washing machines, dryers, blenders, juicers, kitchen fans, coffee machines, etc. The instability detection method includes the following steps:

[0054] Step 101: Acquire first acoustic feedback energy and a first total energy of a first sound signal collected by a reference microphone.

[0055] The first acoustic feedback energy is obtained according to the first control signal of the speaker and the acoustic feedback path. The acoustic feedback path can be obtained based on Wiener filter calibration. For specific implementation methods, please refer to the relevant technical description, which will not be repeated here.

[0056] Furthermore, the calculation formula of the first acoustic feedback energy is:

[0057]

[0058] in, is the first sound feedback energy, is the first control signal of the loudspeaker, is the acoustic feedback path, is the total number of sampling points of the first control signal.

[0059] The calculation formula of the first total energy is:

[0060]

[0061] in, is the first total energy, is the first sound signal collected by the reference microphone, is the total number of sampling points of the first sound signal.

[0062] Step 102: In response to the first acoustic feedback energy and the first total energy meeting an instability condition, determining that the active noise reduction system is instability.

[0063] The instability condition includes at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference between the first total energy and the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than the ratio threshold and the first ratio gradually increases, and the first difference is less than the difference threshold and the first difference gradually increases.

[0064] Furthermore, the calculation formula of the first ratio is:

[0065]

[0066] in, is the first ratio, is the first total energy, is the first sound feedback energy. When an unusual sound is generated in the outside world (such as the sound of cutting vegetables), the reference microphone will also receive the unusual sound, so the sound signal obtained by the reference microphone will become larger. After the sound signal is processed by the controller, the obtained control signal will also increase, so the control signal output by the speaker will also increase. Since both the sound signal and the control signal become larger, the total energy and the sound feedback energy will also increase. By calculating the ratio of the sound feedback energy to the total energy, part of the sound feedback energy can be offset. Therefore, by calculating the ratio, part of the interference of unusual sounds can be offset, thereby making the detection method more accurate.

[0067] The calculation formula for the first difference is:

[0068]

[0069] in, is the first difference, is the first total energy, It is the first sound feedback energy.

[0070] When an unusual sound is generated in the outside world (such as the sound of cutting vegetables), the reference microphone will also receive the unusual sound, so the sound signal obtained by the reference microphone will become larger. After the controller processes the sound signal, the control signal obtained will also increase, so the control signal output by the speaker will also increase. Since both the sound signal and the control signal become larger, the total energy and the acoustic feedback energy will also increase. By calculating the difference between the acoustic feedback energy and the total energy, part of the acoustic feedback energy can be offset. Therefore, by calculating the difference, part of the interference of unusual sounds can be offset, thereby making the detection method more accurate.

[0071] In this embodiment, the present disclosure determines that the active noise reduction system is instability by satisfying the first acoustic feedback energy and the first total energy meeting the instability condition. By calculating the first proportion and the first difference, the interference of the strange sound in the external environment can be effectively offset, thereby avoiding the occurrence of misjudgment of instability of the active noise reduction system. Therefore, the instability detection method can more accurately determine whether the active noise reduction system is in an unstable state.

[0072] In one embodiment, the step of determining the ratio threshold comprises:

[0073] S1: When the active noise reduction system is not unstable, obtain the second acoustic feedback energy and the second total energy of the second sound signal collected by the reference microphone to calculate a second ratio of the second acoustic feedback energy to the second total energy.

[0074] Preferably, the maximum value of the ratio of the second acoustic feedback energy to the second total energy when the active noise reduction system is not unstable may be selected as the second ratio.

[0075] The second acoustic feedback energy is obtained according to the second control signal of the speaker and the acoustic feedback path.

[0076] S2: After adjusting the gain of the acoustic feedback path to simulate instability of the active noise reduction system, obtain the third acoustic feedback energy and the third total energy of the third sound signal collected by the reference microphone to calculate a third ratio of the third acoustic feedback energy to the third total energy.

[0077] S3: Selecting a ratio threshold value within a numerical range from the second ratio to the third ratio.

[0078] In this embodiment, if the ratio threshold is set lower than the second ratio, the active noise reduction system may be too conservative, resulting in poor noise reduction effect; if it is set too high, it may cause the active noise reduction system to become unstable. Therefore, by selecting the ratio threshold within the numerical range from the second ratio to the third ratio, the active noise reduction system can maximize its noise reduction performance while maintaining stability, so as to improve the user experience. In addition, by setting a suitable ratio threshold, preventive measures can be taken when the active noise reduction system may become unstable, so as to prevent the active noise reduction system from becoming unstable in advance.

[0079] It should be noted that step S1 can be performed before the active noise reduction system leaves the factory, that is, the second ratio is determined through experiments, so as to ensure that the active noise reduction system is in an unstable state and there is no environmental noise interference when the second ratio is determined, so as to improve the accuracy of determining the second ratio, and then improve the accuracy of determining the ratio threshold.

[0080] Step S2 and step S3 can be performed before the active noise reduction system leaves the factory, or after it is put into use. Performing them after it is put into use can make the determination of the third ratio conform to the use scenario of the active noise reduction system, and can avoid the third ratio determined not matching the use scenario of the active noise reduction system due to oil pollution contamination of the feedback path or other reasons, thereby affecting the accuracy of the ratio threshold.

[0081] In one embodiment, the step of determining the difference threshold comprises:

[0082] S1: When the active noise reduction system is not unstable, obtain the second acoustic feedback energy and the second total energy of the second sound signal collected by the reference microphone to calculate a second difference between the second acoustic feedback energy and the second total energy.

[0083] Preferably, when the active noise reduction system is not unstable, the interpolation minimum value of the second acoustic feedback energy in the second total energy may be selected as the second difference.

[0084] The second acoustic feedback energy is obtained according to the second control signal of the speaker and the acoustic feedback path.

[0085] S2: After adjusting the gain of the acoustic feedback path to simulate instability of the active noise reduction system, obtain the third acoustic feedback energy and the third total energy of the third sound signal collected by the reference microphone to calculate a third difference between the third acoustic feedback energy and the third total energy.

[0086] The third acoustic feedback energy is obtained according to the third control signal of the loudspeaker and the acoustic feedback path;

[0087] S3: Selecting a difference threshold value within a numerical range from the second difference value to the third difference value.

[0088] In this embodiment, if the difference threshold is set lower than the second difference, the active noise reduction system may be too conservative, resulting in poor noise reduction effect; if it is set too high, it may cause the active noise reduction system to become unstable. Therefore, by selecting a difference threshold within the numerical range of the second difference to the third difference, the active noise reduction system can maximize its noise reduction performance while maintaining stability, thereby improving the user experience. In addition, by setting a suitable difference threshold, preventive measures can be taken when the active noise reduction system may become unstable, so as to prevent the active noise reduction system from becoming unstable.

[0089] In one embodiment, adjusting the gain of the acoustic feedback path to simulate instability of the active noise reduction system includes:

[0090] The gain is reduced in a polling manner with decreasing steps until the active noise reduction system becomes unstable.

[0091] Specifically, only a decrease in the gain of the acoustic feedback path will trigger the instability of the active noise reduction system. This is because when the gain of the acoustic feedback path becomes smaller, the acoustic feedback energy that needs to be removed will decrease, and then the actual noise obtained by the reference microphone will become larger, and the control signal calculated by the controller will become larger. Therefore, it is very likely that the control signal emitted by the speaker will become larger, causing the active noise reduction system to become instable.

[0092] Currently, due to the limitations of the internal layout and structure of each range hood, the acoustic feedback path will be affected by many factors such as the external space. Therefore, it is difficult to quantify its gain. The best way is to use polling to reduce the gain in an appropriate step size. The method can be: the first step is to set the gain; the second step is to calculate the ratio of the acoustic feedback energy to the total energy; the third step is to determine whether there is instability (whether the noise is raised). If there is no instability, the gain is subtracted from the step size, and the previous three steps are repeated until the active noise reduction system becomes unstable to obtain the third ratio.

[0093] It should be noted that the step length may be a fixed value or a dynamic value; when the step length is a dynamic value, the step length is positively correlated with the third ratio, or the step length is positively correlated with the third difference.

[0094] In this embodiment, by polling and reducing the gain in decreasing steps, the third ratio can be found faster and more accurately. For example: when the preset acoustic feedback path gain is 1.0 and the ratio is the third ratio, the corresponding acoustic feedback path target gain is 0.5. If you want to get the target gain more accurately, when polling, you can set the step size to: 0.25, 0.15, 0.1 respectively, so that you only need to poll three times to adjust to the target gain. Compared with setting a fixed step size, such as 0.1, it takes five pollings to adjust to the target gain.

[0095] Figure 3FIG. 1 is a flowchart of determining a ratio threshold in an instability detection method provided by an exemplary embodiment of the present disclosure. The following takes the determination of the ratio threshold before the active noise reduction system leaves the factory as an example to further illustrate how to determine the ratio threshold. Figure 2 .

[0096] S1: The controller is calibrated before leaving the factory with reference microphone and speaker.

[0097] S2: The second ratio is obtained by testing when the active noise reduction system is not unstable, and the third ratio is obtained when the active noise reduction system is unstable.

[0098] S3: Selecting a ratio threshold value within a numerical range from the second ratio to the third ratio.

[0099] In one embodiment, in response to the first acoustic feedback energy and the first total energy meeting the instability condition, the method comprises:

[0100] In response to the first acoustic feedback energy and the first total energy acquired multiple times both meeting the instability condition, it is determined that the active noise reduction system is unstable.

[0101] In this embodiment, the first sound feedback energy and the first total energy obtained multiple times meet the instability condition, which can avoid the misjudgment of instability of the active noise reduction system due to abnormal increase in sound, thereby improving the accuracy of the instability detection method.

[0102] In one embodiment, Figure 4 A flowchart of another instability detection method provided by an exemplary embodiment of the present disclosure, combined with Figure 4 , further illustrating the instability detection method.

[0103] S1: Get the reference microphone to get the sound signal.

[0104] S2: Get the speaker output control signal.

[0105] S3: Calculate the ratio of the acoustic feedback energy to the total energy according to the control signal, the acoustic feedback path, and the sound signal.

[0106] S4: Determine whether the ratio reaches the ratio threshold, if so, go to S6, if not, go to S5.

[0107] S5: Determine whether the ratios obtained multiple times are all increasing. If so, go to S6; if not, go to S2.

[0108] S6: Determine that the active noise reduction system is unstable.

[0109] An exemplary embodiment of the present invention provides a control method for an active noise reduction system. Figure 6A flow chart of a control method of an active noise reduction system provided by an exemplary embodiment of the present disclosure, the control method comprising:

[0110] Step 201: determine whether the active noise reduction system is unstable according to the above instability detection method.

[0111] In step 202, if the judgment result is yes, the active noise reduction system is restarted.

[0112] In this embodiment, restarting the active noise reduction system when it is unstable can, to a certain extent, clear the temporary errors or abnormal conditions that may cause the instability, so that the active noise reduction system can be restored to a stable state, thereby avoiding the howling, which can improve the user experience.

[0113] In one embodiment, the active noise reduction system further includes a controller, the controller being configured to convert the sound signal into a control signal. Restarting the active noise reduction system includes:

[0114] S1: Get the number of consecutive instability of the active noise reduction system.

[0115] S2: In response to the number of consecutive instabilities being greater than or equal to the number threshold, the active noise reduction system is turned off and the controller is optimized; after restarting, the active noise reduction system performs active noise reduction based on the optimized controller. Preferably, the number threshold is set to 10 times.

[0116] The controller can be optimized by LMS algorithm (least mean square algorithm). It should be noted that the specific implementation of the controller marking method can be found in the relevant technical description, which will not be repeated here.

[0117] Furthermore, in response to the number of consecutive instability times being less than the number threshold, the active noise reduction system is directly restarted. If the active noise reduction system fails to become unstable during the restart, the number of consecutive instability times is cleared to zero. If the active noise reduction system is still unstable during the restart, the number of consecutive instability times is increased by 1 and step S1 is performed again.

[0118] In this embodiment, when the number of consecutive instability events is greater than or equal to the number threshold, it indicates that the controller is not matched. During the period when the active noise reduction system is turned off, the controller is optimized in time to improve the stability and noise reduction effect of the active noise reduction system, thereby reducing user dissatisfaction and negative evaluation of the system.

[0119] Corresponding to the aforementioned instability detection method embodiment, the present disclosure also provides an instability detection system embodiment.

[0120] Figure 7 A schematic diagram of a module of an instability detection system provided by an exemplary embodiment of the present disclosure; the detection system is applied to an active noise reduction system; the active noise reduction system includes a speaker and a reference microphone. The detection system includes:

[0121] An acquisition module 71 is used to acquire a first acoustic feedback energy and a first total energy of a first sound signal collected by a reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of a speaker and an acoustic feedback path;

[0122] The response module 72 is used to determine that the active noise reduction system is unstable in response to the first acoustic feedback energy and the first total energy meeting the instability condition; the instability condition includes at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference between the first total energy and the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than the ratio threshold and the first ratio gradually increases, and the first difference is less than the difference threshold and the first difference gradually increases.

[0123] Optionally, the response module 72 includes:

[0124] A first calculation unit is used to obtain the second acoustic feedback energy and the second total energy of the second sound signal collected by the reference microphone when the active noise reduction system is not unstable, so as to calculate a second ratio of the second acoustic feedback energy to the second total energy; wherein the second acoustic feedback energy is obtained according to the second control signal of the speaker and the acoustic feedback path;

[0125] a second calculation unit, configured to adjust the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, obtain a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, so as to calculate a third ratio of the third acoustic feedback energy to the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the speaker and the acoustic feedback path;

[0126] The first selection unit is used to select a ratio threshold value within a numerical range from the second ratio to the third ratio.

[0127] Optionally, the response module 72 includes:

[0128] A third calculation unit is used to obtain the second acoustic feedback energy and the second total energy of the second sound signal collected by the reference microphone when the active noise reduction system is not unstable, so as to calculate a second difference of the second acoustic feedback energy in the second total energy; wherein the second acoustic feedback energy is obtained according to the second control signal of the speaker and the acoustic feedback path;

[0129] a fourth calculation unit, configured to adjust the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, obtain a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, so as to calculate a third difference of the third acoustic feedback energy in the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the speaker and the acoustic feedback path;

[0130] The second selection unit is used to select a difference threshold value within a numerical range from the second difference value to the third difference value.

[0131] Optionally, the third computing unit and / or the fourth computing unit includes:

[0132] The polling component is used to reduce the gain in a polling manner with a decreasing step size until the active noise reduction system becomes unstable.

[0133] Optionally, the response module 72 includes:

[0134] The determining unit is configured to determine that the active noise reduction system is finally unstable in response to the first acoustic feedback energy and the first total energy acquired multiple times both meeting the instability condition.

[0135] Corresponding to the aforementioned control method embodiment of the active noise reduction system, the present disclosure also provides a control system embodiment of the active noise reduction system. Figure 8 A schematic diagram of a control system of an active noise reduction system provided by an exemplary embodiment of the present disclosure, the control system comprising:

[0136] Detection module 81: used to determine whether the active noise reduction system is unstable according to the above instability detection method.

[0137] The restart module 82 is used to restart the active noise reduction system.

[0138] Optionally, the active noise reduction system further includes a controller; the controller is used to convert the sound signal into a control signal; the detection module 81 includes:

[0139] An acquisition unit, used for acquiring the number of consecutive instability of the active noise reduction system;

[0140] The response unit is used to shut down the active noise reduction system and optimize the controller in response to the number of consecutive instabilities being greater than or equal to a number threshold, so that the restarted active noise reduction system performs active noise reduction based on the optimized controller.

[0141] As for the system embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The system embodiment described above is only illustrative, wherein the units described as separate components may or may not be physically separated, and the components as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the disclosed solution.

[0142] Fig. 9This is a structural schematic diagram of a household appliance shown in an example embodiment of the present disclosure, wherein the household appliance includes a memory, a processor, and a computer program stored in the memory and used to run on the processor, and when the processor executes the computer program, the instability detection method or the control method of the active noise reduction system provided in any of the above embodiments is implemented. Fig. 9 The household appliance 90 shown is merely an example and should not limit the functions and scope of use of the embodiments of the present disclosure.

[0143] like Fig. 9 As shown, the home appliance 90 may be in the form of a general computing device, for example, it may be a server device. The components of the home appliance 90 may include but are not limited to: at least one processor 91, at least one memory 92, and a bus 93 connecting different system components (including the memory 92 and the processor 91).

[0144] The bus 93 includes a data bus, an address bus, and a control bus.

[0145] The memory 92 may include a volatile memory, such as a random access memory (RAM) 921 and / or a cache memory 922 , and may further include a read only memory (ROM) 923 .

[0146] The memory 92 may also include a program tool 925 (or utility) having a set (at least one) of program modules 924, such program modules 924 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0147] The processor 91 executes various functional applications and data processing by running the computer program stored in the memory 92, such as the instability detection method or the control method of the active noise reduction system provided in any of the above embodiments.

[0148] The home appliance 90 may also communicate with one or more external devices 94 (e.g., keyboards, pointing devices, etc.). Such communication may be performed via an input / output (I / O) interface 95. In addition, the home appliance 90 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 96. As shown, the network adapter 96 communicates with other modules of the home appliance 90 via a bus 93. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the home appliance 90, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems, etc.

[0149] It should be noted that although several units / modules or sub-units / modules of the household appliance are mentioned in the above detailed description, such division is merely exemplary and not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more units / modules described above may be embodied in one unit / module. Conversely, the features and functions of one unit / module described above may be further divided to be embodied by multiple units / modules.

[0150] The embodiments of the present disclosure further provide a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the instability detection method or the control method of the active noise reduction system provided in any of the above embodiments is implemented.

[0151] The readable storage medium may include but is not limited to: a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical storage device, a magnetic storage device or any suitable combination of the above.

[0152] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A method for detecting instability, characterized in that: The instability detection method is applied to an active noise reduction system; The active noise reduction system includes a speaker and a reference microphone; the instability detection method includes: Acquire a first acoustic feedback energy and a first total energy of a first sound signal collected by the reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of the speaker and an acoustic feedback path; In response to the first acoustic feedback energy and the first total energy meeting an instability condition, it is determined that the active noise reduction system is unstable; wherein the instability condition includes at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference between the first total energy and the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than a ratio threshold and the first ratio gradually increases, and the first difference is less than a difference threshold and the first difference gradually increases.

2. The instability detection method according to claim 1, characterized in that: The step of determining the ratio threshold comprises: When the active noise reduction system is not unstable, obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone to calculate a second ratio of the second acoustic feedback energy to the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the speaker and an acoustic feedback path; After adjusting the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, a third acoustic feedback energy and a third total energy of the third sound signal collected by the reference microphone are obtained to calculate a third ratio of the third acoustic feedback energy to the third total energy; wherein the third acoustic feedback energy is obtained according to the third control signal of the speaker and the acoustic feedback path; Selecting the ratio threshold within a numerical range from the second ratio to the third ratio; and / or, The step of determining the difference threshold comprises: When the active noise reduction system is not unstable, obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone to calculate a second difference of the second acoustic feedback energy in the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the speaker and an acoustic feedback path; After adjusting the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, a third acoustic feedback energy and a third total energy of the third sound signal collected by the reference microphone are obtained to calculate a third difference of the third acoustic feedback energy in the third total energy; wherein the third acoustic feedback energy is obtained according to the third control signal of the speaker and the acoustic feedback path; The difference threshold is selected within a numerical range from the second difference to the third difference.

3. The instability detection method according to claim 2, characterized in that: The step of adjusting the gain of the acoustic feedback path to simulate instability of the active noise reduction system includes: The gain is reduced in a polling manner and in decreasing steps until the active noise reduction system becomes unstable.

4. The instability detection method according to any one of claims 1 to 3, characterized in that: In response to the first acoustic feedback energy and the first total energy meeting an instability condition, determining that the active noise reduction system is instability includes: In response to the first acoustic feedback energy and the first total energy acquired multiple times both meeting the instability condition, it is determined that the active noise reduction system is finally unstable.

5. A control method for an active noise reduction system, characterized in that: The control method comprises: When it is determined that the active noise reduction system is unstable according to the instability detection method according to any one of claims 1 to 4, the active noise reduction system is restarted.

6. The control method according to claim 5, characterized in that: The active noise reduction system further includes a controller; the controller is used to convert the sound signal into a control signal; the restarting of the active noise reduction system includes: Obtaining the number of consecutive instability of the active noise reduction system; In response to the number of consecutive instabilities being greater than or equal to a number threshold, the active noise reduction system is turned off and the controller is optimized; after restarting, the active noise reduction system performs active noise reduction based on the optimized controller.

7. An instability detection system, characterized in that: The instability detection system is used to implement the instability detection method described in any one of claims 1 to 4; the detection system comprises: An acquisition module, used to acquire a first acoustic feedback energy and a first total energy of a first sound signal collected by the reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of the speaker and an acoustic feedback path; A response module is used to determine that the active noise reduction system is unstable in response to the first acoustic feedback energy and the first total energy meeting an instability condition; wherein the instability condition includes at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference between the first total energy and the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than a ratio threshold and the first ratio gradually increases, and the first difference is less than a difference threshold and the first difference gradually increases.

8. An active noise reduction system, characterized in that: A control method for implementing the active noise reduction system according to claim 5 or 6; the active noise reduction system comprises: A detection module, configured to call a restart module when the active noise reduction system is determined to be unstable according to the instability detection method according to any one of claims 1 to 4; A restart module is used to restart the active noise reduction system.

9. A household appliance comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, characterized in that: When the processor executes the computer program, the instability detection method described in any one of claims 1 to 4 or the control method of the active noise reduction system described in any one of claims 5 to 6 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the instability detection method according to any one of claims 1 to 4 or the control method of the active noise reduction system according to any one of claims 5 to 6 is implemented.

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